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The Influence of Environmental Factors on Childhood Height: A Study Reveals Insights
Environmental factors such as socio-economic status, nutrition and infection load influence childhood growth
| Photo Credit: Prashant Nakwe
Significance
A recent study conducted by the Centre for Cellular and Molecular Biology (CSIR-CCMB), along with several other national and international institutions, has revealed that environmental factors play a greater role than genetic variants in determining the height of children in low and middle-income countries (LMICs). This finding contrasts with those from European nations, where genetic aspects predominate in regulating childhood height. Understanding the influence of environmental factors on childhood growth is crucial for addressing issues related to stunted growth and developmental disparities in LMICs.
Features
The study focused on exploring the contribution of modifiable epigenetic factors, including lifestyle, nutrition, and environment, which affect the way genes work. Epigenetic changes influence gene regulation and alter gene expression without altering the DNA sequence. Environmental factors such as socio-economic status, nutrition, and infection load were believed to have a significant impact on childhood growth and height.
Objectives
The primary objective of the study was to investigate the relationship between DNA methylation, genetic variants, and childhood height in various cohorts from India, Gambia, and the UK. By conducting an epigenome-wide association analysis and a genome-wide association study, the researchers aimed to identify potential links and patterns that could shed light on the influence of environmental factors on height variation.
Effects
The study found a robust association between DNA methylation in the SOCS3 gene and height in children from LMICs. This association was also observed in the high-income country cohort, albeit with a lower effect size. The study provided evidence of genome-wide DNA methylation associations with height in children from LMICs. Interestingly, genetic variants associated with height had a lower effect in Indians compared to European and American counterparts, suggesting the role of environmental cues in modifying genetic risk.
Pros and Cons
On the positive side, this study provides valuable insights into the importance of environmental factors in determining childhood height, particularly in LMICs. By understanding the factors that influence height, interventions and strategies can be developed to address the issue of stunted growth. However, the study does not delve into specific interventions or strategies, and further research is needed to determine the exact mechanisms through which environmental factors interact with genetics and epigenetics to impact childhood height.
Fun Fact: Environmental Influences on Human Height
An interesting fun fact related to environmental influences on human height is that genetics only accounts for about 80% of the differences in height among individuals within a population. The remaining 20% is attributed to various environmental factors, including nutrition, lifestyle, and health. This highlights the significant role that environmental factors play in determining human height, indicating that it is not solely determined by our genes.
(Y. Mallikarjun is a freelancer writing on science and health)
Mutiple Choice Questions
1. What factors influence childhood growth in low and middle income countries (LMICs)?
a. Genetic variants
b. Environmental factors such as socio-economic status, nutrition, and infection load
c. Epigenetic changes
d. All of the above
Explanation: According to the information provided, environmental factors such as socio-economic status, nutrition, and infection load influence childhood growth in LMICs.
2. What are epigenetic factors?
a. Genetic changes
b. Lifestyle and environmental influences that affect gene expression
c. Fixed genetic factors
d. DNA sequence alterations
Explanation: Epigenetic factors are external influences, including lifestyle, nutrition, and environment that affect the way genes work. They can alter gene expression but not the DNA sequence.
3. Where are a large proportion of stunted children found, according to the World Health Organization?
a. High income countries (HICs)
b. European nations
c. South Asia and sub-Saharan Africa (LMICs)
d. Gambia and the U.K.
Explanation: According to the World Health Organization, a large proportion of stunted children reside in LMICs, particularly in South Asia and sub-Saharan Africa.
4. What is the role of DNA methylation in gene expression?
a. It regulates gene expression.
b. It alters the DNA sequence.
c. It determines genetic variants.
d. It is influenced by environmental factors.
Explanation: DNA methylation is a chemical modification of DNA molecules used by cells to regulate gene expression. It can be influenced by environmental factors.
5. What association did the study find between DNA methylation and height in children from LMICs?
a. No association was found.
b. The association was stronger in LMICs compared to HICs.
c. The association was weaker in LMICs compared to HICs.
d. The association was only observed in European and American children.
Explanation: The study found a novel, robust association between methylation in the SOCS3 gene and height in children from LMICs. This association was also replicated in the HIC cohort but with a lower effect size.
6. How do genetic risk variations differ between Europeans and Indians?
a. Europeans have higher genetic risk variations.
b. Indians have higher genetic risk variations.
c. The genetic risk variations are largely similar between the two ancestries.
d. There are no genetic risk variations between Europeans and Indians.
Explanation: According to Dr. Giriraj Chandak, the genetic risk variations are largely similar for Europeans and Indians, although the magnitude differs between the two ancestries.
7. What is the role of environmental factors in modifying genetic risk variations in LMIC children?
a. Environmental factors have no effect on genetic risk variations.
b. Environmental factors increase the genetic risk variations.
c. Environmental factors decrease the genetic risk variations.
d. Environmental factors modify the genetic risk variations.
Explanation: Environmental factors appear to modify the genetic risk variations in children in LMICs, according to Dr. Giriraj Chandak. The environmental cues triggering epigenetic processes are different in LMIC children compared to Europeans.
Note: The questions and explanations provided are based on the given information. It is advisable to fact-check and verify the accuracy of the information before using it for exams.
Brief Summary | UPSC – IAS
A study conducted by the Centre for Cellular and Molecular Biology has found that environmental factors play a larger role than genetic variants in determining the height of children in low and middle income countries (LMICs). In contrast, genetic factors dominate in European nations. The study examined the role of epigenetic factors, such as lifestyle, nutrition, and environment, in influencing height. The researchers discovered a strong association between DNA methylation in the SOCS3 gene and height in children from LMICs. European and American children had a lower genetic effect on height compared to Indians, suggesting that environmental factors modify genetic risk in LMICs.